Ovulation Calculator
Default 14 days. Range: 10—16.
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Ovulation Day
Fertile Window—
Next Period Est.—
Cycle Day of Ovulation—
Days Past Ovulation—
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How to Use
Enter the first day of your last period, your average cycle length, and your typical luteal phase length. The calculator determines your ovulation day and fertile window — the 6-day period when conception is most likely.
Ovulation typically occurs 14 days before your next period. The fertile window includes the 5 days before ovulation plus ovulation day itself.
Frequently Asked Questions
You are most fertile during the 6-day fertile window ending on ovulation day. The highest chance of conception occurs in the 2-3 days leading up to ovulation.
The luteal phase is the time between ovulation and your next period. It typically lasts 14 days (range 10-16 days) and is relatively consistent from cycle to cycle.
No. Pregnancy can only occur if sperm meets an egg during ovulation. The egg survives only 12-24 hours after release.
This calculator provides an estimate based on average cycle data. For best results, track your cycle over several months and consider using ovulation predictor kits.